Study on the Influence of Formation Temperature on the Water Absorption and Weathering of Swelling Rock in Marine Coal Mines

To study the mechanisms and potential control measures for coal mine engineering safety hazards caused by swelling rock, water absorption experiments were performed under different temperature by using an independently developed rock water absorption test system. The swelling pressure, expansion amount and water absorption amount of specimens were monitored in real time. Nuclear magnetic resonance and uniaxial compression experiments were performed. The water absorption rate of the swelling rock specimens increases significantly with increasing water absorption time. The water absorption capacity of the specimens differs considerably under different temperatures. The water absorption curve can be divided into three stages: the severe stage, deceleration stage and equilibrium stage. The water absorption amount and water absorption rate are linearly related to temperature. The curve of the swelling pressure depicts a double peak shape. The expansion curve can also be divided into three stages. With increasing temperature, the expansion rate increases, and the time needed to achieve expansion stability is prolonged. There is a negative linear correlation between the uniaxial compressive strength and the moisture content. The higher the temperature is, the higher the moisture content. The increase in the rock porosity after water absorption is one of the important factors driving the strength attenuation.